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1st Grade · 1.MD.A.1

Longest and shortest in 1st grade

Longest and shortest are the words children use to put things in order by length. In 1st grade, your child lines up three objects from shortest to longest. Your child also compares two things that cannot sit side by side, by checking both against a third object.

What the standard says

The official Common Core wording, quoted exactly. The plain version follows.

1.MD.A.1 Order three objects by length; compare the lengths of two objects indirectly by using a third object.

What it means, in plain words

Length is how long something is from one end to the other. To compare lengths fairly, the objects must start at the same place, like runners at a starting line. Lay a spoon and a fork side by side with their ends lined up, and you can see right away which one is longer.

With three objects, your child finds the longest and the shortest, and the third object goes in the middle. Your child learns that longest and shortest compare three or more things, while longer and shorter compare two.

1st grade adds a new kind of comparison: comparing two things by using a third one. Your child cannot carry a couch over to a rug. Your child can cut a piece of yarn as long as the couch and lay it along the rug instead. Whatever is true for the yarn is true for the couch.

Your child should be able to:

  • Line up three objects from shortest to longest, with their ends at one starting line
  • Name the longest and the shortest of three objects
  • Use a third object, such as a piece of yarn, to compare two lengths that cannot sit side by side
  • Use two clues, such as "A is longer than B" and "B is longer than C", to say whether A or C is longer

Example

A spoon, a fork and a toothbrush start at the edge of a table. The spoon ends first, the toothbrush ends last and the fork ends between them. What is the order from shortest to longest?

  1. All three start at the edge of the table, so the comparison is fair.
  2. The spoon ends first, so it is the shortest.
  3. The toothbrush ends last, so it is the longest.
  4. From shortest to longest, the order is spoon, fork, toothbrush.

Example

A piece of yarn is as long as the couch. Laid along the rug, the yarn reaches past the end of the rug. Which is longer, the couch or the rug?

  1. The yarn and the couch are the same length.
  2. The yarn is longer than the rug.
  3. So the couch is longer than the rug too.
  4. The couch is longer.

Where children usually get stuck

  • Your child compares two toys without lining up their ends and picks the one that sticks out farther.

    The child looks only at the far ends and does not notice that the two toys start in different places.

    What helps. Line the toys up against a wall or the edge of a book so both start at the same place, then compare again.

  • Your child says a jump rope curled in a pile is shorter than a wooden spoon.

    The child judges by how much space something takes up, not by its length when stretched out.

    What helps. Stretch the rope out straight next to the spoon and compare again. Then curl it up and ask whether the rope got shorter.

  • Told that a bat is longer than a stick and the stick is longer than a straw, your child cannot say whether the bat or the straw is longer.

    The child reads each clue on its own and does not yet link them through the middle object.

    What helps. Act out clues like these with three real objects from around the house. Line them up, read each clue out loud and check it.

Try four practice questions

Real 1st grade questions from our question bank, easiest first. Answer them right here, check each one, and see a worked solution for any question.

  1. 1Warm-up
    Look at the three pencils below. Which one is the longest?
    Length comparison (3 objects, A→B→C, clear-gap)
    A
    Pencil A
    B
    Pencil C
    C
    Pencil B
    Show the answer and how to solve it

    Pencil A is the longest pencil. When the left ends are lined up, the longest pencil is the one whose right end reaches the farthest.

    1. 1Look at the three pencils. Their left ends are all lined up at the same place. To find the longest one, look at where each pencil ends on the right side.
    2. 2The pencil whose right end reaches the farthest is the longest. Compare all three right ends.
    3. 3Pencil A reaches the farthest to the right. So Pencil A is the longest.

    Common mistake. A common mistake is to pick the wrong end or to compare only two of the three pencils. Always compare all three by looking at where each pencil's right end is.

    The idea underneath. When objects are lined up at one end, the longest is the one that reaches farthest at the other end.

  2. 2On level
    Read these clues about three scarves.
    Clue 1: Eli's scarf is longer than Liam's scarf.
    Clue 2: Maya's scarf is shorter than Liam's scarf.
    Which list shows the scarves from shortest to longest?
    A
    Eli's scarf, Liam's scarf, Maya's scarf
    B
    Liam's scarf, Eli's scarf, Maya's scarf
    C
    Maya's scarf, Liam's scarf, Eli's scarf
    D
    Liam's scarf, Maya's scarf, Eli's scarf
    Show the answer and how to solve it

    The scarves from shortest to longest are: Maya's scarf, Liam's scarf, Eli's scarf. Maya's scarf is the shortest because Clue 2 says it is shorter than Liam's scarf, and Eli's scarf is the longest because Clue 1 says it is longer than Liam's scarf.

    1. 1Look at Clue 1: "Eli's scarf is longer than Liam's scarf." This means Liam's scarf is shorter than Eli's scarf.
    2. 2Look at Clue 2: "Maya's scarf is shorter than Liam's scarf." This means Maya's scarf is even shorter than Liam's scarf.
    3. 3Put both clues together: Maya's scarf is shorter than Liam's scarf, and Liam's scarf is shorter than Eli's scarf. So from shortest to longest, the order is: Maya's scarf, Liam's scarf, Eli's scarf.

    Common mistake. A common mistake is mixing up 'longer than' and 'shorter than'. When Clue 2 says 'Maya's scarf is shorter than Liam's scarf', Maya's scarf is the smaller one and Liam's scarf is the bigger one. Read each clue carefully before deciding the order.

    The idea underneath. Each comparison clue links two objects in order; chain them together using the shared object (here, Liam's scarf) to find the full ordering from shortest to longest.

  3. 3On level
    Read the sentences.
    Zoe's marker is longer than Ben's marker.
    Eli's marker is shorter than Ben's marker.
    Drag each marker into the correct box.
    Drag each item into the group where it belongs, or tap the item, then tap the group.
    Zoe's marker
    Eli's marker
    Ben's marker
    Shortest
    Drag or tap items here
    Middle
    Drag or tap items here
    Longest
    Drag or tap items here

    Keyboard instructions: focus an item and press Enter or Space to pick it up. Move focus to a bin or the bank and press Enter or Space to drop it. Press Escape to cancel.

    Show the answer and how to solve it

    Eli's marker is the shortest, Ben's marker is in the middle, and Zoe's marker is the longest.

    1. 1Read the first sentence: Zoe's marker is longer than Ben's marker. So Zoe's marker is the longer one, and Ben's marker is the shorter one.
    2. 2Read the second sentence: Eli's marker is shorter than Ben's marker. So Eli's marker is the smaller one, and Ben's marker is the longer one.
    3. 3Ben's marker is in both sentences. Zoe's marker is longer than Ben's, and Ben's is longer than Eli's. So Ben's marker is in the middle.
    4. 4From shortest to longest: Eli's marker, Ben's marker, Zoe's marker. Place Eli's in Shortest, Ben's in Middle, and Zoe's in Longest.

    Common mistake. A common mistake is using only the first sentence and guessing where Eli's marker goes. Another mistake is putting Eli's marker in the Longest box because the second sentence uses the word 'shorter' — but 'shorter than' tells you Eli's marker is the smaller one, not the bigger one.

    The idea underneath. When two sentences compare three things, look for the thing that is named in both sentences — that one is in the middle.

  4. 4Stretch
    Clues: The twig is longer than the leaf. The eraser is shorter than the leaf.
    Ana says: "The eraser is longer than the twig."
    Decide which statement is true.
    A
    Ana is wrong. The twig is longer than the eraser.
    B
    Ana is correct.
    C
    Ana is wrong. They are the same length.
    D
    Ana is wrong. The eraser is longer than the twig.
    Show the answer and how to solve it

    Ana is wrong. The clues tell us the twig is longer than the leaf and the eraser is shorter than the leaf, so the twig is longer than the eraser — the opposite of what Ana said.

    1. 1Read the first clue: the twig is longer than the leaf. So the twig is longer than the leaf.
    2. 2Read the second clue: the eraser is shorter than the leaf. So the leaf is longer than the eraser.
    3. 3Chain the clues. The twig is longer than the leaf, and the leaf is longer than the eraser. So the twig is longer than the eraser.
    4. 4Check Ana's claim. Ana says the eraser is longer than the twig. The clues show the opposite — the twig is the longer one. So Ana is wrong.
    5. 5The true statement is: Ana is wrong. The twig is longer than the eraser.

    Common mistake. A common mistake is trusting Ana's claim without checking it against the clues, or thinking two objects each compared to the same third object must be the same length.

    The idea underneath. When two objects are each compared to the same third object, you can chain the comparisons to figure out which one is longer. The object longer than the reference is longer than the object shorter than the reference.